21387240000 has 1400 divisors, whose sum is σ = 96781120128. Its totient is φ = 4561920000.

The previous prime is 21387239941. The next prime is 21387240019. The reversal of 21387240000 is 4278312.

It is a tau number, because it is divible by the number of its divisors (1400).

It is a hoax number, since the sum of its digits (27) coincides with the sum of the digits of its distinct prime factors.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is an unprimeable number.

It is a polite number, since it can be written in 199 ways as a sum of consecutive naturals, for example, 521639980 + ... + 521640020.

Almost surely, 2^21387240000 is an apocalyptic number.

21387240000 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21387240000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (48390560064).

21387240000 is an abundant number, since it is smaller than the sum of its proper divisors (75393880128).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21387240000 is an equidigital number, since it uses as much as digits as its factorization.

21387240000 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 115 (or 81 counting only the distinct ones).

The product of its (nonzero) digits is 2688, while the sum is 27.

The spelling of 21387240000 in words is "twenty-one billion, three hundred eighty-seven million, two hundred forty thousand".